"Oolong versus Son Gokū" (ウーロン対決孫悟空, Ūron Taiketsu Son Gokū; Viz "So Long, Oolong") is the sixth chapter of Part I of the Dragon Ball manga.

Summary

As Oolong, in his bull form, and Son Gokū are about to face off, Oolong becomes cognizant of time and runs off. It is revealed that Oolong's true form is a piglet, and Gokū chases after the shape-shifter but loses sight of him. He comes across the piglet who deceivingly directs him to the bull's escape route. It is also revealed that Oolong's transformation ability is limited by time, as he can transform multiple times within five minutes, but must rest for a minute before he can shape-shift again.

As Gokū returns to the village affirming Oolong's departure, the piglet shape-shifts into an armored giant, threatening to dip Gokū in his hot soup and devour him unless he surrenders. Oolong accidentally burns his finger from the hot soup, and a small child attacks the giant with a slingshot. Gokū hypothesizes that Oolong isn't as strong as he lets on, causing the giant to become defensive.

Oolong then dares Gokū to break a stack of bricks to test the boy's confidence, to which Gokū completes the task with merely a finger. A shocked Oolong changes into a bat and attempts to flee, but Gokū, commanded by Bulma to catch the bat in order to save the girls for the village, uses his Kintoun to catch Oolong in his tracks. Oolong, in his bat form, transforms into a missile, only to revert to his original form from running out of time to maintain his shape-shifting ability.

Gokū saves the piglet from falling and returns to the village, where the citizens not only realize that Oolong is weak, but that his true form is simply a piglet. As Gokū restrains Oolong, the humiliated piglet takes the villagers to his mansion, only to find out that the "captured" girls were having a better time in the mansion than they were in the village.

Bulma, after retrieving two Dragon Balls, drives a speedboat in search for the rest of the mystical spheres along with Gokū and Oolong, with Bulma wanting to utilize the transformation ability of the latter. Bulma tempts a begrudged Oolong by claiming she'll sleep in her underwear in order to get the piglet to cooperate. Gokū, curious to figure out Oolong's gender, pats the piglet in his groin, much to the ire of the pig.